Resettable circuit breaker



Dec, 8, 1956 c. E.- BUCK ET AL 23%,44

RESETTABLE CIRCUIT BREAKER Filed Nov. 12, 1952 INVENTORS CHAEL 5 E. BUCK A25 KL 6 G. Mu TZENH/SEB m, vvwwwvalg,

dew ATTORNEYS United States Patent 2,714,844. ESETT BLECI CUI'FB AKER Application November 1-2, 1952, Serial No 3195858 4 Cl m (Ql:-:2.0Q

This invention relatesto electriccircuit'breakersof the type that areautomatically-operable to break the circuit cont-rolled thereby in event thata current greater than that which can be safely carried by said circuitis passed therethroughi I Y Devices of this type are provided to prevent damage and are generally inthe form of removable fuses which are burned out by. an excess current. a The burned out fuse is useless and must be replaced before the circuit can be againclosedi This might be dangerous in case an important circuit is openedin this'manner and said circuit cannot be, used again until a new fuse is substituted for'that destroyed.

An object ofi the present invention into-provide an improved automatic circuit breaker which will automatically open a circuit, if such circuit carries an excess current, but. will not; be damaged by the excess current, and which will. be rendered effective to release the circuit whenever the circuit is opened thereb Another object of the present inye nt on is to proyidea Q ICuit breaker having a membcrautomatically. rnovable to a circuit opening position if an excess current: is passed through said circuit and manuallyoperable means for; moving and holding the miember in a circuit closed position after the circuit has been broken.

' Another object of the present invention is to provide a thermostatic circuit breaker which will have constant contact pressures up to the time of separation of the contacts and when the contacts separate they will separate with a snap action, thus eliminating arcs and consequently burning of the contact surfaces.

Another object of the present invention is to provide a latching connection for an automatic circuit breaker which does not carry current, thus the breaker calibration is not subject to change in case there is arcing and burning at the contacts.

Further objects and advantages of the present invention will be apparent from the following disclosure, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown. I

In the drawings:

Fig. 1 is a plan view of the switch embodying the features of the present invention.

Figure 2 is a central vertical section of Figure 1.

Fig. 3 is a view similar to Fig. 2 but showing the switch in its closed position. a A

Fig. 4 is a detail sectional view showing the switch parts in position before the parts of the switch are latched in the switch closed position.

The device disclosed herein, although applicable to control any electric circuit, was designed primarily to control various electrical circuits of an automotive ve hicle, such as headlights, parking lights, etc.

Referring to the drawings, a fragment of a base or supporting block 20 fabricated from a suitable dielectric material is shown. This base has holes, not shown, through which attaching members are insertable for se- Ratented Dec. 18, 1956 curing the base in any'suitable position. In the present instance the baseisshown as supporting only one switch, butitis to beunderstood however, that as many as these devices as desired may be supported in spaced relation by the base 20--to control as many separate circuits as neces sary.

The base 20 is formedwith-a recess 21, grooves or channels22 and 23, eachcommunicating with the recess 21 and a counterbored opening 24- to provide a shoulder 25. Eachswitch adapted to be supported on the base 20- iscomposed=- of relativelywide resilient-metallic strip material to provide a conductor 2owhich is bent to form a base portion 27 which fits in the. groove22. The conductor 26 is bent upwardly from the base portion 27 to provide a-portion 28 and then: inwardly to provide a re silient or flexible arm 2 9which overlies the base and the opening 24; The arm 29 is provided with an opening 30 aligned with the opening 24 and; carries a contact 31. The arm 29 in its-normal state is inclined toward the base 20, as shown in Figi 2 and normally occupies such a; position that the contacts are separated. Before the base portion 27- is'placed in the groove 22, a conducting plate 32yisplacedtherein to which a lead, not shown, of a circuitfto be controlled by the automatic breaking means is adapted to be connected. The base portion 27 and the plate 32 are secured to the base by a rivet 33. The sides of the grooves 22 cooperate withv the side edges ofthe plate 32 and the base 27 of the conductor 26 to prevent them from; turning relative to the base 20.

The base 20 also supports a bimetal' element or'thermostatic st-rip 40 bent;- into the shape as shown to provide arms 41 and 42* and an upstanding portion 43. The arm 42 of; element 49 extends into the groove 23 to prevent the element from turning relative to the base 20. The element 40 is more sensitive to heatwhen overloaded by excessive electric current flowinthe circuit controlled by the circuit breaker. The element 40 undergoes disto'rtion when so heated by an overload of electric current passing through it. The element 40 has an arm 4z-securea to the base 20 by a rivet 45 which also sea cures a conducting plate 46 in contact with the element 40 to the base as clearly shown in Fig. 2. The plate 46 provides a terminal for the switch for connection to a lead, not shown, of the circuit to be controlled by the switch.

A push button or actuator or plunger 50, is mounted for vertical movement in the opening 24 of the base 20. In this instance the actuator is made of metal. The push button is formed with an annular flange 51 intermediate its ends which cooperates with the shoulder 25 to limit the downward movement thereof as viewed in Fig. 2. The upper end of the plunger is formed with a latching groove 53, adapted to receive the free end of arm 41, and a cone-shaped end 54. The plunger passes through and has a loose fit in an insulating flanged bushing 55 which has its shank extending through the opening 30 of the arm 29. A compression spring 56 surrounding the plunger is disposed between the bushing 55 and the collar 51 and held under compression by the resilient arm 29 to bias the plunger 50 downwardly until the flange 51 bears against the shoulder 25.

When a circuit to be controlled is in its open position the switch parts assume approximately the positions shown in Fig. 2 wherein the free end of the arm 41 of thermal element 40 is above the cone-shaped end 54 of the plunger and the contacts 31 and 44 are separated. When it is desired to close the circuit breaker the operator pushes the plunger 50 upwardly, as viewed in Fig. 2. As the plunger is moved upwardly the coiled spring 56 is further compressed because of the resisting force in the flexible arm 29. When the spring 56 is compressed a certain amount it will overcome the resisting force of the arm 29 so that the arm will be moved by the spring 56 until contact 31 engages contacts 44. When that happens both arms 26 and 40 are moved together upwardly causing the cone-shaped end to engage the free end of arms 41 and move portion 43 in a counterclockwise direction, see Fig. 4, until the free end of the arm 41 is opposite the groove 53. When this happens the element 40 tends to return to the normal state with the free end of arm 41 entering the groove 53 to lock the switch in circuit making position, as shown in Fig. 3. The spring arm 29 always tends to separate contact 31 from contact 44 and the spring 56 tends to move the plunger 50 downwardly but these actions are prevented by the latching action of the element 40. If a current is passing through the circuit controlled by contacts 44, 31, and the circuit temperature does not exceed a predetermined degree, the parts of the switch remain in the position shown in Fig. 3, and the circuit remains closed. If there is a short circuit or for other reasons an excess current is passed through the circuit which is sufiicient to heat the element above a predetermined degree, the element 40 moves to the left sufiiciently to free the arm 41 from the groove 53. The instant the arm is out of the groove 53 the arm 29 and the plunger will be forced downwardly by the spring action of arm 29 so that the circuit breaker will stand in open position. As soon as the circuit is opened the bimetal strip 40 begins to cool and returns to its normal state without engaging the plunger.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. An automatic circuit breaker, comprising in combination; a bimetallic strip member having a freely moveable end and a fixed end mounted to a support, a flexible strip member having one end fixed to said support and having the other end free to move and normally spaced from said bimetallic member, a moveable plunger movable relative to and adopted to move the free end of said flexible member into contacting engagement with said bimetallic member, and a means on said plunger engageable with the free end of said bimetal member for maintaining said members in said contacting engagement until the bimetallic member thermally responds to a predetermined current passing therethrough and causes said means to be released.

2. An automatic circuit breaker, comprising in combination; a bimetallic strip member having a freely moveable end and a fixed end mounted on a support, a second strip memberhaving one end fixed in spaced relation to said bimetallic member on said support and the other end normally spaced from said bimetallic member, a moveable plunger spaced between the fixed ends of said members adapted to move said second member into engagement with said bimetallic member and means on said plunger engageable by the free end of said bimetallic member for holding said members in said en-- gagement.

3. The construction of the character described in claim 2 wherein the means for maintaining the members in engagement includes a notch extension on the plunger that is adapted to pass through an aperture in the second member and is adapted to form a latching engagement with the bimetallic member, when the members are in engagement.

4. The construction of the character described in claim 1 wherein a spring surrounds said plunger and is en-' gageable with the member moved thereby so as to be compressed when said plunger is moved for forming the contacting relation between said members.

References Cited in the file of this patent UNITED STATES PATENTS 1,372,207 Stahl Mar. 22, 1921 1,492,967 Donle May 6, 1924 2,079,812 Olds May 11, 1937 2,114,026 Mayer Apr. 12, 1938 2,148,880 Stattler Feb. 28, 1939 2,191,588 Stattler Feb. 27, 1940 2,262,205 Schachtner Nov. 11, 1941 2,344,946 Landon Mar. 28, 1944 2,458,804 Sundt Jan. 11, 1949 2,577,425 Marcoz Dec. 4, 1951 2,615,963 Millen Oct. 28, 1952 2,633,515 Locher Mar. 31, 1953 

